FR2471989A1 - PROCESS AND COMPOSITIONS FOR THE PREPARATION OF POLYMERS AND COPOLYMERS OF VINYL CHLORIDE - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS AND COMPOSITIONS FOR THE PREPARATION OF POLYMERS AND COPOLYMERS OF VINYL CHLORIDE. THE PROCESS CONSISTS OF A SUSPENSION POLYMERIZATION IN THE PRESENCE OF A REDOX CATALYTIC SYSTEM INCLUDING A PEROXYGEN COMPOUND CHOSEN FROM PEROXYESTERS AND DIACYL PEROXIDES, AND STANNO CHLORIDE.

Description

"Process and compositions for the preparation of poly-

  The present invention relates to a vinyl chloride suspension polymerization process using a redox catalyst system comprising a peroxyester or a diacyl peroxide and

stannous chloride.

  The suspension polymerization of vinyl chloride is generally carried out at temperatures

  below 70 C using organic initiators

  Although lauroyl peroxide has long been the most widely used catalyst, it has been adopted in recent years.

  other catalysts for low temperature,

  These catalysts and others have been described by Pennwalt Corporation, Lucidol Division, Technical Bulletin 30, 90, "Free Radical Initiators for Bioavailability."

  the Suspension Polymerization of Vinyl Chloride "(1977).

  The choice of the initiator is determined by

  its half-life and its influence on the poly-

  The polymerization of vinyl chloride is characterized by a short period of induction, followed by a gradually increasing rate of polymerization. During the early stages of the polymerization, the polymerization of vinyl chloride is characterized by a short period of induction.

  reaction rate is less than the maximum value

  the, so that the capacity of the reactor is not all-

  talementutilisée. Peroxyesters reduce the period

  of induction and, because of a more constant rate of

  lymerization, they increase the productivity of the reaction

  tor. In addition, peroxyesters can generally be used at lower rates than required

  for peroxides and they give much less

  chain mification during polymerization.

  Although peroxyesters such as peroxydi-

  diisopropyl carbonate and t-peroxypivalate

  butyl offer many advantages in the polymer-

  vinyl chloride, they also have disadvantages, including the need for transport and storage under low temperature conditions,

  and lower efficiency at high temperatures.

  The use of peroxyesters with

  higher temperatures of decomposition are not practically

  in the current production facilities

  of povinyl chloride, because of the highest pres-

  the monomers involved, as well as the low molecular weight and the lower stability of the

  resulting resins. Nevertheless, the benefits of

  of these peroxyesters make their use

extremely interesting.

  Use at lower temperatures

  catalysts for higher temperatures

  is a common practice in technology

  polymers. This is how systems are used

  my redox, such as an ammonium persulfate system

  sodium metabisulfite and a hydrogen peroxide system

  ferrous sulfate-gene in the emulsion polymerization

  while a peroxide system of benzoyl dimethylaniline and a peroxide system of

  cobalt methyl ethyl ketone-naphthenate in the

  lymerization of unsaturated styrene-polyester.

  Reducing agents used together with monomeric-soluble peroxyesters, in

  polymerization of vinyl chloride, are in particular

  potassium bisulfite (N.Fischer and C.Lambling, French Patent 2,086,635, 1972), sodium bisulfite (H.Minato, K.Hashimoto, and TY sui, Japanese Patent 68 / 20,300,1968), a sodium bisulphite system cupric chloride (BK Shen, United States patent

  3,668,194, 1972), a sodium-sulfonated dithionite system

  ferrous (H.Minato, Japanese Patent 70 / 04,994, 1970) and trialkylbores (R.Kato and I.Soematsu, Japanese Patent 65/5498, 1965); A.V.Ryabov, V.Ao DOdonov and Y.A. IVanova, TroKhim. Tekknol., 1970, 238; Stockholms Superfosfat Fabriks A / B, British Patent 961,254,

1964).

  Reducing agents used in conjunction with the diacyl peroxides soluble in the monomer,

  in the polymerization of vinyl chloride, are

  also a ferrous sulphate-hydroxide system of

  dium (AMSharetakii, So V.Svetozarakii, E.NoZil'berman, and IBKotlyar, British Patent 1,164,250, 1969, and U.S. Patent 3,594,359, 1971), ferrous caproate, ( JoUlbricht and NVThanh, Plaste Kaut., 21, 186, 1974); J.Ulbricht and G. Mueller, Plaste Kauto,

  21, 410 (1974) and trialkyl borates (A. V. Ryabov, V.A.

  Dodonov, and Y.A.Ivanova, Tr.Khim.Tekknol., 1970, 238)

  The water-soluble reducing agents con-

  better for emulsion polymerization than for bulk or suspension polymerization, the

  presence of iron compounds is detrimental to the

  properties of polyvinyl chloride and the trialkyl

  res react with oxygen and require manipula-

tion.

  An object of the present invention is to

  see a vinyl chloride polymerization process in the presence of peroxygen compounds at temperatures

  where they are stable and manipulated

  slow easily. Another object of the present invention is to provide a method for suspension polymerization of vinyl chloride at temperatures

  less than 701C using peroxygen compounds

  which, at these temperatures, do not generate radi-

  at a rate sufficient to initiate a poly-

  merit at a practical level, as long as it

  there is such a formation of free radicals.

  It has now been found that these improvements in the polymerization of vinyl chloride can

  to be achieved using a catalytic system

  dox comprising a peroxyester or a diacyl peroxide

and stannous chloride.

  According to the present invention, the polymerization

  vinyl chloride is carried out according to a suspension system under the conditions

  applicable and well known to specialists, using

  reading a catalytic system comprising a peroxy-

  ter or a diacyl peroxide soluble in the monomer

  re, and a reducing agent which is stannous chloride.

  The half-life of a catalyst promoting the formation of free radicals is the necessary time.

  to achieve a 50% decomposition at a temperature of

  particular character. The half-life is of interest only with regard to the temperature at which it is desired to conduct a polymerization, for example the polymerization of vinyl chloride below 700C to produce polyvinyl chloride of greater stability thermal that a polymer produces above 700C. The half-life of a peroxyester is thermal decomposition and, therefore, if polymerization is to be conducted at 50 ° C., a catalyst having a half-life of 20 hours or less at 50 ° C can be employed for

  polymerization, for example peroxypivalate from

  butyl or t-butyl peroxyneodecanoate, as known to those skilled in the art.

  However, if it is desired to conduct the polymerization

  With a catalyst which does not require refrigerated conditions for transport and / or storage, which is however necessary for t-butyl peroxypivalate and t-butyl peroxyneodecanoate, it can be used according to the present invention. a

  catalyst with a half-life of 50 hours at 50 C in pre-

  of a suitable reducing agent, eg

  t-butyl peroxyoctoate which has a half-life of 133 hours

  at 50 ° C in the absence of the reducing agent.

  Alternatively, if one wishes to conduct a

  polymerization at 25 C or below or if you want to

  to better control the exothermic nature of the reaction or to obtain a less branched polymer of higher molecular weight, it is possible to use, despite

  their transport and refrigeration storage requirements.

  managed, the peresters mentioned above, of one-half

  life of more than 150 hours at 25 C, in the presence of a

appropriate reducing agent.

  The method of the present invention utilizes a

  peroxygen compound, such as a peroxyester or peroxide

  dialkyl hydroxide, in the presence of a reducing agent

  appropriate, at a temperature at which the compound

  roxygenated has a half-life of more than 50 hours in the ab-

the reducing agent.

  The peroxyesters that can be used in the process of the present invention are peroxyesters

  alkyl and aralkyl carboxylic acid

  or aromatic or carbonic acid and they may be represented by the following structural formulas:

R-0-0 - R '

  wherein R is an alkyl, aralkyl or alkoxycarbonyl group, R 'is an alkyl, aralkyl, aryl or alkoxy group, and R and R' are the same or different. When R and / or R 'contain

  alkyl or aralkyl moieties, these may

  1 to 20 carbon atoms, they can be

  mayors, secondary or tertiary, linear -or

  branched, acyclic or cyclic, saturated or unsaturated

  res, and they may contain non-hy-

  hydrocarbons, in particular halogen and hy-

  droxyle. When R 'is an aromatic moiety, it may be unsubstituted or may contain substituents

  hydrocarbons, halogens and / or others.

  Peroxyesters may be monoperoxy

  esters or diperoxy esters of dicarboxylic acids

or diols.

  Examples of peroxyesters are: peroxyacetone

  t-butyl acetate, t-butyl peroxyisobutyrate, peroxygen

  t-butyl pivalate, t-butyl peroxyneodecanoate, t-butyl peroxybenzoate, t-butyl peroxyoctoate,

  t-butyl peroxy (2-ethylhexanoate), peroxynodeodecanoate

  t-amyl ester, cumyl peroxneodecanoate, peroxypi

  isobutyl valate, secondary butyl peroxybenzoate,

  n-butyl peroxyoctoate, peroxy-3,3,5-trimethylhexa

  t-butyl noate, t-butyl peroxy-2-methylbenzoate,

  2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane:, 2,5-

  dimethyl-2,5-bis (benzoylperoxy) hexane, 2,5-dimethyl-2,5-

  bis (octanoylperoxy) hexane, t-butyl diperoxyphthalate,

  t-butyl peroxymaleate, peroxyisopropylcarbonate of t-

  butyl, di (sec-butyl) peroxydicarbonate, peroxydicar-

  bis (4-t-butylcyclohexyl) bonate, peroxydicarbonate

  diisopropyl, di (n-propyl) peroxydicarbonate, peroxidic acid

  di (2-ethylhexyl) carbonate, di-peroxydicarbonate

  cyclohexyl, dicetyl peroxydicarbonate, etco

  Aliphatic diacyl peroxides, especially

  acetyl peroxide, lauroyl peroxide, decanoyl peroxide and isononanoyl peroxide,

  as well as aromatic dialkyl peroxides, especially

  benzoyl peroxide, p-chloro-peroxide

  benzoyl and 2,4-dichlorobenzoyl peroxide may be used together with the reducing agents of the present invention at a temperature at which

  diacyl peroxide has a half-life of more than 50 hours

  in the absence of the reducing agent.

  The process of the present invention is carried out with a redox catalyst system comprising a peroxygen compound, soluble in the monomer, and

  a reducing agent, insoluble in the monomer, at

see stannous chloride.

  The molar ratio between the peroxygen compound and the reducing agent is generally 1 / 0.01-2, a preferred ratio being of the order of 1 / 0.1-1. The concentration of the peroxygen compound is usually

  0.01-5% by weight of vinyl chloride, a

  preferred concentration being of the order of 0.05 to 1%

in weight.

  Stannous chloride which can be used as a reducing agent in the present invention can

  be the anhydrous salt or the hydrated salt.

  The reaction of diacyl peroxides and peroxyesters with stannous chloride in acid solution was used in the quantitative analysis of peroxygen compounds. According to a method, the

  reaction with benzoyl peroxide and peroxygen

  of phthaloyl was conducted with excess chlorine

  stanneux in acid solution, and the standard chloride

  The non-used solution in the hot solution was titrated back with a standard solution of iodine. In another method, the analysis of benzoyl peroxide was carried out by maintaining a mixture of

  peroxide and stannous chloride in acetic acid.

  tick at room temperature for one hour, with

  then added a boiling solution of iron alum

  in sulfuric acid and ammonium chloride.

  monium. The ferrous ions formed by the reaction with the unused stannous chloride were titrated with a solution of potassium dichromate using diphenylamine sulfonic acid as an indicator. These methods have been described by R.M.Johnson and I.W.Siddiai, "The determination of Organic Peroxides", Pergamon Press,

1970, pages 4E-41.

  The recommended process for the analysis of the

  t-butyl xyoctoate comprises the addition of a solution of

  stannous chloride in acetic acid to

  a solution of the peroxyester in acetic acid.

  The mixture is allowed to react at room temperature for 10 minutes and the unreacted stannous chloride is then titrated back with potassium iodate solution (Pennrwalt Corp.,

  Lucidol Division, Analytical Procedure P-52-1, 1976).

  The reaction of the peroxygen compounds with stannous chloride in the presence of acetic acid is

  apparently fast and sufficiently complete at the

  ambient temperature to serve as a quantitative titration method. Despite the absence of any disclosure as to the nature of the intermediates, that is to say radical or ionic, or as to the products of the reduction of peroxygen compounds, the extreme speed of the reaction excludes its use

  in the polymerization of vinyl chloride.

  This was confirmed by a suspension polymerization test of vinyl chloride in the presence of t-butyl peroxyoctoate, stannous chloride and acetic acid. The polymer yield was% after 13 hours at 50 ° C., indicating that the solubilization of stannous chloride in vinyl chloride, due to the presence of acetic acid, resulted in the rapid decomposition of the peroxyester and an inability to effectively initiate the

  polymerization of vinyl chloride.

  On the other hand, when acetic acid is omitted, the suspension polymerization of vinyl chloride in the presence of t-butylperoxyoctoate and stannous chloride surprisingly gives a yield of 82%.

  polymer at 13 hours at 500 C. This may be

  tribute to the interaction of stannous chloride insoluble in monomer with peroxyester, in chloride

  vinyl, at a slow pace at the interface of the drip

liters of water and monomer.

  In the absence of stannous chloride, the peroxygen

  t-butyl octoate does not initiate suspension polymerization of vinyl chloride after 20 hours

at 50 C.

  The processes normally used in the poly-

  suspension merification of vinyl chloride are applicable to the present invention. Examples of processes have been described in Encyclopedia of Polymer

  Science and Technology, 339-343 (1971).

  Polymerization can be carried out under pressure

  atmospheric pressure or at a higher pressure. In the-

  the usual process, the reactor is loaded to the

  atmospheric pressure and the pressure rises when the

  reactor contents are brought to the reaction temperature

  pressure can increase further due to the exothermic nature of the reaction and then remain constant until the conversion reaches 70%,

  after which it decreases rapidly while the reaction

continued.

  The polymerization temperature can be from -5C to + 70WC for bulk polymerization,

  although temperatures of 400 to 600C are preferred.

  The suspension polymerization can be carried out at temperatures of +5 to + 701C, although

  temperatures of the order of 200 to 600C.

  The concentrations of monomer and water, for example in a weight ratio of about 2: 1, and the types and concentrations of suspending agents are those normally used in suspension polymerization and are well known in the art.

  specialists. Examples of suspending agents

  are polyvinyl alcohol, polyvinyl acetate, polyvinyl

  partially saponified vinyl, gelatin,

  ethylcellulose, a copolymer of vinyl acetate and maleic anhydride, etc. Various emulsifying agents, such as sulfonated oils and

  the condensation products of ethylene oxide,

  adjust the surface tension and the shape of the

  ticles. If necessary, buffers may be used, for example when gelatin is used as a suspending agent. Agents can be used

  chain transfer, such as chlorinated hydrocarbons

  res and isobutylene, in the preparation of a

low molecular weight lymere.

24 71989

  Although the catalyst system comprising a peroxygen compound and stannous chloride, following

  the present invention is particularly interesting.

  In the suspension polymerization of vinyl chloride, this redox system can also be used in the copolymerization of vinyl chloride with

  vinylidene chloride, vinyl acetate and

  monomers that undergo copolymerization with

vinyl chloride.

  Various examples of implementation of the present invention are presented below but they are not of course in any way limiting the scope of this patent,

EXAMPLE I

  The following suspension composition is loaded into a glass bottle with a capacity of 113 g: 21 ml of distilled water (slurry), 1 ml of an aqueous solution containing 1% Tween 60 (polyoxyethylene sorbitan monostearate) Atlas Chemical Industries Inco) 1 ml of a 1% aqueous solution of Span 60 (sorbitan monostearate, Atlas Chemical Industries Inco), 2 ml of a 1% aqueous solution of Methocel A-15

  (methylcellulose with a viscosity of 15

  peas in the form of an aqueous solution

2%, Dow Chemical Co).

  The solution is bubbled with nitrogen

aqueous for 15 minutes.

  Gaseous vinyl chloride is purified by passing through two aqueous solutions at 5%

  of sodium hydroxide, followed by drying by

  wise through a column of silica gel and

2471989 '

  densification with a dry ice bath. After addition of 10 g of liquid vinyl chloride and 0.052 g (0.23 mmol) of stannous chloride dihydrate

  in the suspension composition, the bottle is fer-

  mated by a screw cap having a central hole and a self-sealing gasket. The addition of 0.055 ml (0.23 mmol) of t-butyl peroxyoctonoate (0.5% by weight of the vinyl chloride) is made by injection

  through the joint with a hypodermic syringe.

  The bottle is placed in a constant temperature bath

  aunt 50 C and shaken for 13 hours. The bottle is removed from the bath and the residual monomer is released

  by introducing a needle into the joint. The production

  of polyvinyl chloride is 8.2 g (conversion

82%).

EXAMPLE II

  A bottle is charged in the same manner and with the same reagents as in Example I, except that the stannous chloride dihydrate is omitted. There

  no polymer isolation after 20 hours at 50 C.

EXAMPLE III

  A bottle is charged in the same manner and with the reactants as in Example I, except that 2 ml of glacial acetic acid is added to the mixture.

  reaction prior to the addition of the t-bu-peroxyoctoate

  tyle. After 13 hours at 50 C, the production of chlorine

  Polyvinyl chloride is 0.5 g (5% conversion).

  Although particular embodiments of the invention have been described above, this is not

  obviously not limited (to the details given because many

  its variants and modifications can be considered

  without departing from the scope of this patent.

* - E

Claims (7)

  l.Process for the preparation of polymers and co-polymers   polymers of vinyl chloride, characterized in that it consists of a suspension polymerization in the presence of a redox catalytic system comprising a peroxygen compound chosen from peroxyesters and   diacyl peroxides, and stannous chloride.   2. The process of claim 1, wherein   characterized in that the polymerization is conducted at a temperature at which the peroxygen compound has a half-life of more than 50 hours in the absence of stannous chloride.   3. Process according to claim 2, characterized   in that the polymerization temperature is of the order of -50 to + 70 ° C., in particular of 20 to 60 ° C.   4, Process according to any one of the   1 to 3, characterized in that the peroxyester is chosen from alkyl peroxyesters of aliphatic carboxylic acids and carboxylic acids. aromatic and carbonic acid.   5. Process according to claim 4, characterized   characterized in that the peroxyester is peroxyoctoate t-butyl.   6. Process according to any one of   p: ecOebs, characterized as diacyl leperoxide is   selected from 1-aroyl peroxide and benzoyl pracyF.   7. Catalytic compositions for the preparation of polymers and copolymers of vinyl chloride,   characterized in that they comprise a compound   xygen selected from peroxyesters and peroxides   of diacyl, and stannous chloride.